The problem with the DMR is less about the gun itself and its balance or lack of, its about how a hitscan starting weapon affects map building.

In H3 you could have big open maps like Standoff where the best you could hope from the BR at long range would be to take a potshot that makes soemoen duck into cover but that was about it. In H4, the long range game is dominated by the DMR's high accuracy & hitscan. So maps with open spaces are a no no. Even a small map like the Pit wouldnt work in H4 as the sniper towers would be instant death from DMR fire.

So the consequence of the DMR is that most of the maps have a load of clutter in the middle of the map to cut down on cross map DMR kills. Which means everyone has limited eyelines and its hard to get around. Which means it is hard to call out enemies as you can't see across the map, and hard to support team mates as you have to negotiate whatever the big thing in the middle of the map happens to be.

I love using the DMR but to be honest, it is a contributing factor in the shitty map layout in H4.